1. Field of the Invention
The present invention relates generally to providing therapy to the region of the jaw, and more particularly, to devices and methods for increasing temporomandibular joint range of motion while strengthening a user's jaw muscles, and for massaging the jaw muscles, optionally at the same time, and additionally to devices and methods for inducing forward mandibular translation for related therapeutic purposes.
2. Description of Related Art
Prior U.S. Pat. No. 5,183,057 and No. 5,562,105, on which I am named as a co-inventor, disclose a particularly effective device for improving temporomandibular joint range of motion. As noted in these related patents, this type of device is useful in many circumstances, one of the most important being as part of post-treatment therapy after medical procedures such as temporomandibular joint surgery, temporary intermaxillary fixation, facial infections, and trauma to the face, and as therapy for other medical conditions affecting the temporomandibular joint. One embodiment of the device uses a hollow bellows pump to force water into a bellows actuator between two hinged members placed between the user's teeth, thus separating the members and opening the user's mouth. The pump bellows is disposed in a separate housing, where it is compressed by a spring to force water into the actuator bellows. The user then bites down on the members to urge them together and force the water back into the pump bellows, after which the biasing spring operates to reopen the user's jaw. Repeatedly closing his or her mouth against the resistance provided by the spring exercises the temporomandibular joint and strengthens the user's jaw muscles.
This device is particularly effective and convenient when used solely in a mode in which the pump is operated by the user to passively stretch his or her jaw muscles to increase temporomandibular joint range of motion. In an embodiment of the patented device designed for that purpose, the hinged members are biased into a closed position and the user inserts the device into the mouth between the upper and lower jaws, after which the user manually squeezes the pump bellows to force the upper and lower jaws apart. When the pump bellows is released, the members are automatically returned to their closed position. But the embodiment described further above, which is designed also to strengthen the user's jaw muscles, is somewhat cumbersome to use and does not permit precise control of the resistance against which the user contracts the jaw muscles or the rate at which the user's jaw is reopened. These can be serious drawbacks since particular care must be taken when exerting these muscles in the circumstances in which the device is used, such as after temporomandibular joint surgery when the jaw is particularly vulnerable to damage if exercised too vigorously.
Other known devices used to manipulate a user's temporomandibular joint to increase range of motion, strengthen jaw muscles, or for other purposes, are shown in the following references:
U.S. Pat. No. 3,813,096U.S. Pat. No. 4,280,696U.S. Pat. No. 5,035,420U.S. Pat. No. 5,582,560U.S. Pat. No. 5,846,212U.S. Pat. No. 6,050,961U.S. Pat. No. 6,361,475U.S. Pat. No. 6,413,231U.S. Pat. No. 6,558,392U.S. Pat. No. 7,238,145U.S. Publ. No. 2007/0012319U.S. Publ. No. 2007/0089752U.S. Publ. No. 2007/0287598U.S. Publ. No. 2010/0011916    “TheraBite® Jaw Motion Rehabilitation System,” Brochure of Atos Medical AB, Hörby, Sweden (undated).    “E-Z Flex™ Exerciser,” Brochure of Fluid Motion Biotechnologies, Inc., New York, N.Y. (1996).    Tiwari, Bhawana, et al., “A New Dynamic Jaw Exerciser,” Indian Jour. of Dental Sciences, Vol. 2, No. 2, pages 4-6 (2010).
None of these references discloses a device designed to increase temporomandibular joint range of motion in a manner precisely controlled by the user and at the same time strengthen jaw muscles by permitting repeated motion of the muscles against a calibrated resistance that the user can precisely adjust as part of a controlled exercise program.
Massage therapy can also be an effective treatment for temporomandibular joint and jaw muscle disorders, either alone or in combination with range of motion and/or strengthening exercises. While an individual can self-administer massage, most laymen are not trained in proper massage therapy techniques. Accordingly, self-massage in practice can be largely ineffective. By the same token, using a trained massage therapist can be expensive and inconvenient, and therefore not done with sufficient frequency to have maximum efficacy. Most individuals would likely find it preferable to be able to administer massage therapy themselves in a manner that they can be certain is safe and effective. It would be even more advantageous if massage therapy, with or without the application of heat or cold, could be administered in conjunction with exercises for improving temporomandibular joint range of motion and/or strengthening jaw muscles.
In addition to devices that involve opening and closing the mouth to exercise or administer therapy to jaw muscles, there are also devices that induce translation of the lower jaw (“mandible”) back and forth (that is, in an anterior-posterior plane) to administer therapy to the jaw muscles and increase temporomandibular range of motion. The E-Z Flex™ jaw exerciser referred to above included a translation adapter that could be used to move the mandible forward for therapeutic reasons. U.S. Pat. No. 5,846,212 also discloses a mandible translator intended for therapeutic applications.
The mandibular translation device disclosed in U.S. Pat. No. 5,846,212 comprises two plates mounted for face-to-face sliding motion, with mouthpieces for the upper and lower teeth on the respective plates. That device and the translation adapter for the E-Z Flex™ jaw exerciser are operable only in a modality that requires user manipulation to return his or her mandible rearward to its natural position after being translated forward. In the case of the '212 patent, the user must directly manipulate the plates by hand to translate his or her mandible forward and backward. This gives rise to variations in the amount and/or rate of movement, which can be detrimental in some therapy regimens. In the E-Z Flex™ device the user has to exert a force with his mandible to translate it posteriorly. That may not be acceptable in some therapy regimens in which strictly passive mandible movement is indicated. Alternatively, the user can move the adapter with his or her hands to return the mandible to a non-protruding position, but that will be awkward with the adapter in the user's mouth and could cause injury to tissues associated with the temporomandibular joint.
A related issue involving mandibular translation is the treatment of obstructive sleep disorders, such as sleep apnea and snoring. A known treatment involves a user wearing a mandibular repositioning device that holds the mandible in a forward protruded position to prevent blockage of the airway to the lungs when the user is sleeping in a supine position. One of the issues in administering this type of therapy is properly fitting such devices to a particular user. Optimally, such devices hold the user's mandible in a forward position the minimum amount necessary to maintain the airway to the lungs open, without placing undue stress on the temporomandibular joint. It is known to pre-measure mandible translation during sleep tests prior to fitting such a device (see, for example, U.S. Pat. No. 6,155,262 and U.S. Publ. No. 2010/0316973), and to take diagnostic images of a user's jaw at different open positions (see for example, U.S. Pat. No. 4,834,112). But it is not known to pre-measure for the minimum amount of mandibular translation that should be imparted by a repositioning device while actually viewing the user's mouth parts as the mandible is held in a forward translated position.